This invention relates to a method of forming a closed end on a knitted tubular fabric, particularly on a stocking, using a circular knitting machine.
In a known method of forming such an end, the tubular fabric is held on supporting members (which may consist of the circular array of dial hooks in a one-cylinder machine or may comprise some of the needles transferred to the upper cylinder in a two cylinder machine) while a further section of tubular fabric is formed by action of needles in a lower needles-cylinder, and relative rotation between the circle of support members and the lower needle cylinder through at least 180.degree. is effected. The loops held on the said support members are then transferred to the needles of the lower cylinder which effectively doubles the said further section of tubular fabric.
After the transfer, which, together with twisting of the fabric due to the relative rotation referred to above, brings about closure of the end, a few more rounds of virtually run-proof close stitching are knitted before casting-off from the cylinder needles is effected. These rounds of close stitching form in effect a small cord at the edge of the double fabric, away from the closed end.
When the aforesaid system is used for making a stocking it suffers from the disadvantage that, owing to the formation of the small cord, the stocking has limited elasticity and stretch, precisely in a region where this elasticity and stretch are most required. Moreover, the presence of the cord generally causes annoyance to the user when walking since it exerts unpleasant pressure upon the sole of the foot.
For this reason it has already been proposed to form the closed end of a tubular fabric, particularly at the end of a stocking, by forming two separate layers of fabric, supporting the free end of one layer on a circle of support members while twisting the layers relative to each other, and then transferring the end of the said layer from its supporting members to the needles of the lower cylinder. This results in the cord which consists of the rounds or rows of close finishing-off stitching being close to the toe end of the tubular fabric, rather than at the edge of the double fabric away from this closed toe end, or in any case closer to the toe end than the aforesaid edge of the tubular fabric.
According to a known process, after the last row of the tubular fabric has been formed, an inner and an outer annular layer of tubular fabric, both continuous with the aforesaid tubular fabric, are formed. The end of the inner layer is held upon support members arranged in a circle whilst the end of the outer tubular layer is held on the needles of the lower cylinder of the machine, and a relative rotation through at least 180.degree. is effected between the said circle of support members and the cylinder. The loops held upon the said support members are then transferred on to the needles of the lower cylinder, and a few turns or rows of substantially run-proof close stitching, are made before the fabric is cast-off.
In the foregoing method the inner and outer layers of the double fabric of the closed end are formed simultaneously, the inner layer by the action of the support members and the outer by the action of at least some of the needles of the lower cylinder of the machine.
This method can be used with either a two-cylinder circular machine or with a single cylinder circular machine which is, however, of a special type, in which there is a series of horizontal cam-controlled needles in the radial grooves of the dial.
In the first case, some of the needles, e.g. alternate needles of the lower cylinder, are transferred to the upper cylinder, and the outer layer of the double fabric is made by the needles operating in the lower cylinder, whilst the inner layer of the fabric is made by the needles operating in the upper cylinder, and it is therefore necessary to have at least two thread guides, one of which feeds the yarn to the needles of the lower cylinder and the other to those of the upper cylinder. Upon completion of the two layers the two cylinders are rotated relatively to each other through at least 180.degree., and the needles operating in the upper cylinder are transferred to the lower cylinder, after which all the needles carry out a few rounds of substantially runproof close knitting, to form the small finishing-off cord which will thus be closer to the closed end than to the other edge of the double fabric.
In the second case, the inner layer of the double fabric is made by the horizontal needles on the dial, and the respective free edge is transferred, after rotation of the dial relative to the cylinder has been effected, to the needles of the lower cylinder, which then carry out the turns or rows of close finishing-off stitches.
This known process does, however, have some serious disadvantages which render its reliability, or even the possibility of its practical embodiment on an industrial scale, questionable.
In both cases it is impossible with the previously known method to use a machine capable of knitting according to a single system. Thus a one-cylinder circular knitting machine of the simplest and most widely used type, having a dial furnished with hooks, cannot be used.
The object of this invention is to avoid this disadvantage and to provide a highly reliable method which can be carried out without difficulty with any type of circular stocking knitting machine, having either two-cylinders or a single-cylinder, even with only one operating system, so long as it is provided with a mechanism allowing reciprocal rotation between the two cylinders or between the cylinder and the dial.